Add GetDBConnector interface

gorm.go

@@ -331,8 +331,8 @@ func (db *DB) AddError(err error) error {
 func (db *DB) DB() (*sql.DB, error) {
 	connPool := db.ConnPool
 
-	if stmtDB, ok := connPool.(*PreparedStmtDB); ok {
-		connPool = stmtDB.ConnPool
+	if dbConnector, ok := connPool.(GetDBConnector); ok && dbConnector != nil {
+		return dbConnector.GetDBConn()
 	}
 
 	if sqldb, ok := connPool.(*sql.DB); ok {

interfaces.go

@@ -57,3 +57,7 @@ type TxCommitter interface {
 type Valuer interface {
 	GormValue(context.Context, *DB) clause.Expr
 }
+
+type GetDBConnector interface {
+	GetDBConn() (*sql.DB, error)
+}

prepare_stmt.go

@@ -18,6 +18,18 @@ type PreparedStmtDB struct {
 	ConnPool
 }
 
+func (db *PreparedStmtDB) GetDB() (*sql.DB, error) {
+	if dbConnector, ok := db.ConnPool.(GetDBConnector); ok && dbConnector != nil {
+		return dbConnector.GetDBConn()
+	}
+
+	if sqldb, ok := db.ConnPool.(*sql.DB); ok {
+		return sqldb, nil
+	}
+
+	return nil, ErrInvaildDB
+}
+
 func (db *PreparedStmtDB) Close() {
 	db.Mux.Lock()
 	for _, query := range db.PreparedSQL {